Siemens Understanding Battery Depassivation: How to Depassivate Battery Meaning for Optimal S7-400 Performance

Commissioning

Reducing the Passivation Layer

Lithium batteries (lithium/thionyl chloride) are used as backup batteries for the

S7-400. In lithium batteries of this technology, a passivation layer can develop after storage for a very long time, and the immediate functional capability of the battery may not be certain. This may result in an error message when the power supply module is switched on.

The power supply modules of the S7-400 are capable of reducing the passivation layer of the lithium battery with a defined load on the battery. This process may take some minutes. When the passivation layer has been reduced and the lithium battery has reached its rated voltage, the error message of the power supply module can be acknowledged with the FMR button.

Since the storage time of the lithium battery is not usually known, we recommend the following procedure:

•Insert the backup battery/batteries in the battery compartment.

•Acknowledge any battery error message of the power supply module with the FMR button.

•If the battery error cannot be cleared, try again after a few minutes.

•If the battery error still cannot be cleared, remove the battery/batteries and short-circuit it/them for one to three seconds maximum.

•Reinsert the battery/batteries and try to acknowledge with the FMR button again.

•If the battery error message goes off, the battery/batteries is/are operational.

•If the battery error message does not go off, the battery/batteries is/are discharged.

Removing a Backup Battery

Chapter 7 describes how to remove the backup battery (batteries).

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